1. Field of the Invention
The present invention relates to a printed circuit board having a contact or terminal portion which is suitable to be electrically contacted by a probe or pin device or structure.
2. Description of the Related Art
When the establishment of electrical contact among printed wiring or printed circuit boards is necessary, configurations such as depicted in FIGS. 1(a) and 1(b) often are utilized.
Referring now to FIGS. 1(a) and (b), nine land portions 31-39 are formed at the end portion of a printed circuit board 30. Probes 41-49, as shown in FIG. 1(a), respectively contact lands 31-39. Probes 41-49 are probes (e.g., search units) of a device for the inspection of the printed circuit board 30 which is typically carried-out during manufacturing or repairing processes.
The width A of a land portion (e.g., land portion 31) is set so as to permit proper and effective contact with a probe device (e.g., probe 41) of the type mentioned above. The spacing C of the land is set to a necessary distance to accommodate a conductor's width and the pitch of a connector device. Such an arrangement is necessary so that no two conductors of a connector or probe can contact each other to thereby cause a short circuit to occur.
The spacing B between adjacent lands is set such that the interval distance C equals land width A+the spacing B. Accordingly, land space in the case of a set of nine lands 31-39 becomes 8C+A (see FIG. 1(b)) and is set according to the size, precision, and location of probes 41-49 and the corresponding conducting probes.
If the distance between lands is reduced while maintaining the land space of the printed circuit board 30 at spacing B, smaller size probes 41-49 or an increase in the accuracy of their positioning is necessary. However, when using a custom article, such as a miniaturized set of probes 41-49, an increase in their mounting position precision involves a corresponding increase in manufacturing cost.
For an additional discussion of electrical contact systems of the type mentioned above, reference is made to U.S. Pat. No. 5,021,812 to Kohno et al.